Rogal Dorn / Warhammer / Dornian Heresy
Dorn saw the Imperium not as a great civilization, but as a dying fortress built on fear, lies, and the Emperor's secrets. While the other Primarchs still believed in the dream of the Great Crusade, he could already hear the walls of the doomed empire creaking.
He didn't consider himself a traitor.
He considered himself the last man willing to do what the Emperor himself hadn't dared.